Journal of Power Sources 164 (2007) 567–571 Short communication Thin yttria-stabilized zirconia electrolyte and transition layers fabricated by particle suspension spray Ruiqiang Yan, Dong Ding, Bin Lin, Mingfei Liu, Guangyao Meng, Xingqin Liu ∗ USTC Laboratory for Solid State Chemistry & Inorganic Membranes, Department of Materials Science and Engineering, University of Science and Technology of China (USTC), Hefei 230026, PR China Received 4 October 2006; received in revised form 14 November 2006; accepted 17 November 2006 Abstract In order to develop high performance intermediate temperature (<800 ◦ C) solid oxide fuel cells (SOFCs) with a lower fabrication cost, a pressurized spray process of ceramic suspensions has been established to prepare both dense yttria-stabilized zirconia (YSZ) electrolyte membranes and transition anode layers on NiO + YSZ anode supports. A single cell with 10 m thick YSZ electrolyte on a porous anode support and ∼20 m thick cathode layer showed peak power densities of only 212 mW cm -2 at 700 ◦ C and 407 mW cm -2 for 800 ◦ C. While a cell with 10 m thick YSZ electrolyte and a transition layer on the porous anode support using a ultra-fine NiO + YSZ powder showed peak power densities of 346 and 837 mW cm -2 at 700 and 800 ◦ C, respectively. The dramatic improvement of cell performance was attributed to the much improved anode microstructure that was confirmed by both scanning electron microscopes (SEM) observation and impedance spectroscopy. The results have demonstrated that a pressurized spray coating is a suitable technique to fabricate high performance SOFCs and at lower cost. © 2006 Elsevier B.V. All rights reserved. Keywords: SOFCs; Suspension spray; Dense YSZ electrolyte; Transition anode layer 1. Introduction Solid oxide fuel cells (SOFCs) as electrochemical energy conversion devices have attracted extensive studies because of their high energy efficiency, simple operation and environmen- tal friendliness. In recent years, anode supported thin electrolyte SOFCs have demonstrated a high power density, even at tem- peratures around or below 800 ◦ C. In fabrication of anode supported SOFCs, there have been a number of techniques developed to prepare thin electrolyte layers on anode supports, such as aerosol-assisted metal-organic chemical vapor deposi- tion (MOCVD) [1], polarized electrochemical vapor deposition (PEVD) [2], RF magnetron sputtering [3], screen printing [4], slurry coating [5] process, etc. The techniques involving gaseous process are generally of quite high cost in both equipment and operation, and of rather low efficiency, which makes them difficult to scale up for commercialization. The other conven- ∗ Corresponding author. Tel.: +86 551 3606249; fax: +86 551 3607627. E-mail address: xqliu@ustc.edu.cn (X. Liu). tional ceramic processing methods usually use large amounts of organic additives, which may lead to large shrinkages associated with the removal of additives on subsequent drying and sinter- ing, and thus it is difficult to fabricate dense thin membranes with a larger area on porous supports. Conventional slurry pro- cessing remains but some problems are still to be solved, such as a low green density, a large pore distribution of the green layer and cracks during drying. A suspension spray process has been commonly considered as a low cost technique for the prepara- tion of functional ceramic layers in SOFCs. Though there were reports to mention that some companies had employed this tech- nique to fabricate YSZ layers, but there is no detailed description in the literatures. To improve the microstructure and to increase triple phase boundaries (TPB) of the positive–electrolyte–negative (PEN) assembly, it is usual to deposit a transition layer on the as- prepared porous anode support by some process. In this work, we developed a pressurized suspension spray coating [6] to directly fabricate both the ultra-fine transition anode layer and the YSZ electrolyte layer on a porous anode support. Fuel cells have been assembled and tested. 0378-7753/$ – see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.jpowsour.2006.11.060